三叉神経節に関する実験的研究

Abstract

Pulp exposure and application of arsenious acid were experimentally made in the mandibular first molars of rats and histo-pathological investigations were made of their respective effect on the trigeminal ganglion cells and of the changes in the nerve fibers of the pulp in the two experiments. The results were as follows : 1. In the exposed-pulp group, necrosis occurred in the pulp surface layer on the first day after pulp exposure and progressed with time thereafter. The necrosed tisuses extended nearly to the apical foramen on the 14th day after pulp exposure. Thereafter, formation of abscess in the apical periodontium was observed. 2. With the development of the foregoing necrosed tissues, the nerve fibers of the pulp gradually repeated degeneration and resolution and disappeared. 3. In the exposed-pulp group, ganglion cells indicative of displacement of the nuclei and disappearance and irregularity of Nissle substance were observed in the trigeminal ganglion in the operated side. Quantitative observations showed an increase with time in the proportion of the ganglion cells until the 14th day after pulp exposure and a decreasing tendency thereafter. 4. In the arsenious acid application group, destruction of the pulpal blood vessels and disturbance of the circulation were recognized from the first day after application. Although no significant changes in the pulp cells were observed at this time, the pulp tissues were found destroyed with time. 5. In the arsenious acid application group, collapsed images of the nerve fibers were recognized as early as on the first day after application. In the chronolngical findings also, nearly all the pulpal nerve fibers were found destroyed. 6. In the arsenious acid application group also, ganglion cells indicative of the similar findings as those observed in the exposed-pulp group were recognized in the trigeminal ganglion in the operated side. Quantitatively, the proportion of the ganglion cells increased on the 3rd and/or the 7th day after application and decreased thereafter. 7. Morphological changes in the trigeminal ganglion cells occurred relatively early in the arsenious acid application group and about a week later in the exposed-pulp group. 8. On the basis of the observation results of the nerve fibers in the experiment site and the trigeminal ganglion cells, the quantitative changes on the prefixed days of the trigeminal ganglion cells which were morphologically changed approximately correspond with the changes in the nerve fibers in the experiment site.